Turkey and Russia are close to signing a contract for supplying of S-400 missile systems, Russian defense giant Rosoboronexport said Tuesday.

“The contract is close to signing, but has not been signed yet and, accordingly, has not yet entered into force,” Rosoboronexport general director Alexander Miheyev said, adding that “the work continues, technical nuances remain.”

A contract to supply S-400 anti-aircraft missile systems to Turkey is in the final stages, but has not yet been signed or entered into force, the head of Russian defense giant Rosoboronexport said, retracting his previous statement reported by RIA Novosti.

“The contract to supply Turkey with S-400s is ready, but has not been signed or entered into force,” Rosoboronexport Director General Aleksey Mikheev told reporters on Tuesday, adding that “the work is still ongoing, technical issues remain.”

Earlier RIA Novosti quoted Mikheev as saying “the contract has been signed, but it has not entered into force yet.”

Russia and Turkey have been discussing the contract since November 2016, with top officials from both countries repeatedly confirming that the deal has been “agreed upon” and arrived “at the final decision point.”

Turkey has agreed to pay Russia $2.5 billion for the S-400 systems, a Turkish official said July 13, making the country the first NATO member country to purchase the S-400 defense system.

With the purchase of the S-400’s, Ankara aims to build Turkey’s first long-range air and anti-missile defense system to guard against threats in the region. Moreover, Turkey seeks to build its own missile defense systems as the S-400 deal also involves transfer of technology and know-how.

The S-400 missiles, which were introduced in 2007, are the new generation of Russian missile systems, and so far Russia has only sold them to China and India.

Russian-made S-400 system is capable of shooting down aircraft at ranges of up to 400km and ballistic missiles at a range of 60km. It can engage up to 36 targets simultaneously and can use various missile types for different targets. The Russian Army has already received the most sophisticated batch of missiles for the S-400, capable of shooting targets in the nearest space, according to military officials.

The defense system is able to carry missiles, which has the capability to destroy ground and air targets, including ballistic and cruise missiles.

PS the deal does not create concern only to US and the Pentagon but also to Greece. S-400 missiles right outside our door?